<html>
<head>
<script>
function createDynamicForm() {
  var dynamicForm = document.createElement('form');
  dynamicForm.setAttribute('name', 'dynamic_form');
  dynamicForm.setAttribute('id', 'dynamic_form_id');
  dynamicForm.setAttribute('method', 'post');
  dynamicForm.setAttribute('action', 'done.html');
  dynamicForm.setAttribute('onsubmit', 'return true;');

  var inputUsername = document.createElement('input');
  inputUsername.setAttribute('type', 'text');
  inputUsername.setAttribute('name', 'username');
  inputUsername.setAttribute('id', 'username_id');

  var inputPassword = document.createElement('input');
  inputPassword.setAttribute('type', 'password');
  inputPassword.setAttribute('name', 'password');

  var submitButton = document.createElement('input');
  submitButton.setAttribute('type', 'submit');
  submitButton.setAttribute('value', 'Submit');

  dynamicForm.appendChild(inputUsername);
  dynamicForm.appendChild(inputPassword);
  dynamicForm.appendChild(submitButton);

  document.body.appendChild(dynamicForm);
}
</script>
</head>
<body>
<input type='button' id='create_form_button' onclick='createDynamicForm()'>
</body>
</html>
